/Engine/Source/Runtime/Engine/Public/ParticleEmitterInstances.h
Called from Tick to determine whether the emitter will no longer spawn particles checks for emitters with 0 loops, infinite lifetime, and no continuous spawning (only bursts) and sets bEmitterIsDone if the last burst lies in the past and there are no active particles bEmitterIsDone is checked for all emitters by ParticleSystemComponent tick, and the particle system is deactivated if it's true for all emitters, and if bAutoDeactivate is set on the ParticleSystem
void CheckEmitterFinished()